Drug discovery recently has experienced tremendous growth, facilitated in part by novel technologies, such as combinatorial chemistry and high-throughput screening. These novel approaches have led to drugs that generally are more potent and have better solubility and activity profiles than drugs developed from traditional approaches of medicinal chemistry. The discovery of such drugs has resulted in a more urgent focus on developing novel techniques to deliver these drugs more effectively, efficiently, and safely.
The conventional oral and intravenous routes of drug administration do not provide ideal pharmacokinetic profiles, especially for drugs that display high toxicity and/or narrow therapeutic windows. For such drugs the ideal pharmacokinetic profile would be one wherein the drug concentration reaches therapeutic levels without exceeding the maximum tolerable dose and maintains these concentrations for extended periods of time until the desired therapeutic effect is reached. One approach for achieving such a profile is encapsulating the drug in a polymer matrix.
Although efforts have been made to develop suitable polymer matrices for drug delivery, there remains a need in the art for compositions and methods for therapeutically effective and safe delivery of a drug to a subject. Compositions and methods that provide for drug delivery on demand, localized drug delivery, sustained or controlled-release of a drug, or improved drug stability are particularly advantageous.